I cant open it - Eureka 431A Optima Bagless Upright Vacuum

Before doing anything, make sure that the vacuum is unplugged from the outlet. After that, you are now ready to open your vacuum. Here are the steps to do so:
a) First, remove the dust cap by pressing the "cup release" button on the top rear right of the cleaner and pulling the dust cap away from the top. Set aside.
b) These first three steps are optional, but will make the process a bit easier... Now remove the hose attachment by twisting the base of the hose clockwise until the tabs line up and allow you to easily remove. Set aside.
c) Now remove the floor nozzle attachment by depressing the silver lock button located on the bottom back of the cleaner. While this is pressed in, pull the body of the vacuum and the carpet cleaning nozzle away from each other. (This is easier with two people, but can be done alone.) These steps will make the cleaner less bulky for you to take apart and work with.
1) Now on the back of the cleaner, you will see 9 screws. (3 on each side of the rear of the body, 1 on each side of the rear base of the body, and 1 in the middle of the hose actuator valve [the knob that switches between floor and hose]). Unscrew all of these and set them aside. *see note at bottom
2) Now that these 9 screws are removed and placed aside, you will now be able to remove the rear panel of the vacuum. Do so and move it out of your way. Keep in mind that the power cord runs through a hole in this panel and cannot be removed entirely without disconnecting wires (which I wouldn't recommend if you don't know what you're doing).
3) Now on the inside rear of the cleaner, your should see 1 screw in the top right holding the power cord in place. 1 screw below that on the right side holding a number of white and black wires in place. There will be 1 screw on top right of the gray plastic that the floor nozzle had attached to, and 1 on the bottom left. There are also 2 screws at the same height (1 on the left and 1 on the right) about a quarter way up from the bottom screwed into the green plastic on the left and right of the gray plastic floor nozzle attachment. Remove these 2 screws.
4) Now look on the outside left and right of the base of the cleaner. You should see 4 screws (2 on each side). Remove these.
5) Now you should be able to remove the front panel to expose the motor which will be surrounded by black foam and resting in a circular hole in the bottom. Voila! You have now opened up your vacuum cleaner.

*Something to keep in mind before removing the screw from the hose actuator valve is to pay attention to the position of the knob. Also look inside the hole of the hose coupling while turning the knob to note how the valve moves inside the cleaner. When reassembling, make sure that this is in the correct position.